1. Field of the Invention
The invention comprises to an acrylate adhesive composition and plasters or dressings containing same, the adhesive strength of which composition does not sustain any losses even under humid conditions.
2. Discussion of Background Information
Adhesive compositions have a broad range of uses in the production of wound treatment products, if they contain only minimal amounts of residual monomers due to a high degree of polymerization and can thus be considered to be particularly well tolerated by the skin.
A number of printed publications in this respect disclose various acrylate compositions and rubber pastes, such as, e.g., EP 352901, EP 238863, JP 1060677, U.S. Pat. No. 4,269,747, U.S. Pat. No. 5,876,855, JP 10152662, DE 42 22 334, DE 196 31 422, DE 102 13 759, WO 9625469 or WO 9723577. The production of polymer matrices, in particular gel matrices, from polyacrylates has been known for many years and is described, e.g., in EP 0 507 160, JP 11-228340 and JP 04178323.
The main object of the adhesive compositions used is thereby a secure adhesion of the wound treatment product to the skin and an easy and in particular pain-free removal from the skin at the end of the application period.
However, this most important property of a plaster, which is also repeatedly cited in consumer polls, cannot be achieved in every case. Depending on the liquid absorption capacity of the wound dressing and/or the adhesive composition as well as on the water-vapor permeability of the plaster, perspiration or sweating lead to more or less frequent undesirable detachment of plasters.
In the prior art there has been no lack of attempts to master these disadvantages and to develop an improved, less moisture-sensitive adhesive composition, such as, e.g., through the additional use of superabsorbents or through hydrophilization.
For acrylate adhesive compositions the use of hydroxyethyl acrylate or hydroxyethyl methacrylate for hydrophilization is described, e.g., in U.S. Pat. No. 5,302,629.
Adhesive compositions based on synthetic rubber can be hydrophilized by the addition of a so-called surfactant, as described in U.S. Pat. No. 6,860,961.
Another problem in the cross-linking of polyacrylic acid to form a self-adhesive matrix or gel is that a matrix once produced with defined physical properties, viscosity, adhesiveness, etc. must have the same defined properties in a later production process. This reproducibility is expensive to realize or cannot be realized at all with the cross-linking technologies currently known.
It is known from a completely different technical field that, e.g., barnacles and mussels can achieve a perfect waterproof adhesion. 3,4-Dihydroxyphenylalanine (DOPA) thereby plays an important role, after repetitive sequences of DOPA-containing decapeptides have been identified in the protein that has proven to be responsible for the adhesion, as stated in the literature (J. H. Waite, J. Biol. Chem. 258, 2911-2915 [1983]). The mechanism of the sticking and the firm adhesion then occurring of these organisms via so-called MAPs (“Mussel Adhesive Proteins”) has also been explained (M. Yu et al., J. Am. Chem. Soc. 121, 5825-5826 [1999]).
After the so-called mussel adhesive has been identified, it was possible according to US 20030087338 to incorporate this principle into synthetic polymers. In US 20030087338 this principle is based on the chemically synthesized L-3,4-dihydroxyphenylalanine containing decapeptide described above that represents a sequence from the MAPs of the mussel mytilis edulis. This decapeptide can be conjugated to different polymers in order to generate a biomimetic adhesive composition. The cross-linkage of DOPA groups to form the biomimetic adhesive composition analogous to the MAPs can be carried out enzymatically or oxidatively. However, the oxidative cross-linking leads to losses in adhesive strength. US 20030087338 therefore also describes oxidation-independent aggregation and/or gelation phenomena for producing corresponding polymers or copolymers. Polyethylene glycols or polyalkylene oxides are represented as possible polymers or copolymers. A combination with acrylate-containing adhesive compositions is not disclosed. The described decapeptide synthesis essential for the production of the biometic adhesive composition has furthermore proven to be complex and time-consuming.
The object of the present invention is to provide adhesive compositions, in particular acrylate adhesive compositions, which have a better adhesive strength compared to the prior art and are less moisture-sensitive. In particular, the object of the present invention is to provide an adhesive composition that can be combined with the principle of the waterproof adhesion of barnacles and mussels without the unfavorable circumstances and disadvantages of the decapeptide synthesis having to be taken into consideration.